[NTG-context] font clarification

[jbf]

Can someone clarify a font issue for me please.

I have the following setup:

\definefontfamily[mainface][rm][TeX Gyre Pagella]
\definefontfamily [mainface] [ss] [Arial][tf=file:arial:ttf]
\definefontfamily [mainface] [mm] [TeX Gyre Pagella Math]
\setupbodyfont[mainface,11.5pt]

When I look at what this produces, I see that my body text is in fact 
texgyrepagellamath-regular. If I run mtxrun --script font --list --file 
-pattern=*pag*, I see, among others, the following:

texgyrepagellamath   ...    texgyrepagellamathregular 
texgyrepagella-math.otf   conflict: regular
texgyrepagella   ...    texgyrepagellaregular 
texgyrepagella-regular.otf   conflict: regular

So three questions:

1. Does Tex Gyre Pagella Math contain everything I need for my body font 
(ignore Arial - I use that for drop caps and a few other things and it 
works as it should)?

2. If so, do I still need the first line in my setup, namely the [rm] 
line? Would not the [mm] be enough?

3. The mtxrun output suggests there is a 'conflict' between 
tgpagella-regular and tgpagella-math. What is the nature of this 'conflict'?

It is possible that my questions reveal a basic misunderstanding of this 
typeface. Don't hesitate to tell me so but also try to put me right.

Julian